1. Technical Field
The invention relates to an internet data delivery system and more particularly, to a multi-level redirection system for use with an internet.
2. Related Art
A content delivery network (CDN) is a mechanism that delivers some or all content from cache servers distributed at multiple locations. CDNs include origin servers and cache servers. Some or all of the contents of web responses may be served with the cache servers and therefore, the origin servers may significantly reduce work load. Further, fast response may be provided to users. The cache servers may be distributed at multiple locations around the network. Some or all of the contents of the origin servers are cached or mirrored at the cache servers. When a web request comes in, CDNs try to locate an appropriate cache server to serve the request. For example, the appropriate cache server may be close to a user geographically, or in terms of a network distance between the cache server and a user's machine.
One of known CDN techniques is a domain name system (DNS) redirection, which is described in U.S. Pat. No. 6,108,703 to Leighton et al. In U.S. Pat. No. 6,108,703, embedded objects are served from one of multiple cache servers. To locate an appropriate cache server, DNS servers determine a user's location in the network and provide a user with an IP address mapped to a cache server adjacent the user's location. A user requests the embedded objects to the cache server and receives the desired response from the cache server.
Although other redirection techniques may be available, conventional CDNs operate at one level by redirecting some or all contents for a request from origin servers to cache servers.